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Stimulus frequency differentially affects chirping in two species of weakly electric fish: implications for the evolution of signal structure and function

Authors :
Sara E. Sanford
Johanna A. Kolodziejski
G. Troy Smith
Source :
Journal of Experimental Biology. 210:2501-2509
Publication Year :
2007
Publisher :
The Company of Biologists, 2007.

Abstract

SUMMARY During social interactions, apteronotid electric fish modulate their electric organ discharges (EODs) to produce transient communication signals known as chirps. Chirps vary widely across species and sex in both number and structure. In Apteronotus leptorhynchus, males chirp far more than females and their chirps have greater frequency modulation than those of females. High-frequency chirps are produced by males most often in response to female-like electric signals. As such, they have been hypothesized to function in courtship. The more common low-frequency chirps, produced by both males and females in response to same-sex signals, are hypothesized to function as aggressive signals. To determine whether the two chirp types in the closely related Apteronotus albifrons have similar functions, we stimulated chirping in male and female A. leptorhynchus and A. albifrons with playbacks simulating the EODs of same-sex versusopposite-sex conspecifics. As in A. leptorhynchus, male and female A. albifrons produced low-frequency chirps most often to same-sex signals. Unlike A. leptorhynchus, however, A. albifrons also produced more high-frequency chirps to same-sex stimuli than to opposite-sex stimuli. This suggests that high-frequency chirps in A. albifrons,unlike those in A. leptorhynchus, may not function as courtship signals and that the function of similar chirp types has diversified in Apteronotus. Examples such as this, in which the function of a communication signal has changed in closely related species, are rare. The electrocommunication signals of apteronotids may thus provide a remarkable opportunity to investigate the evolutionary interactions of signal structure and function.

Details

ISSN :
14779145 and 00220949
Volume :
210
Database :
OpenAIRE
Journal :
Journal of Experimental Biology
Accession number :
edsair.doi.dedup.....da9edcd2becf96c80bd0f56c05eda5e2
Full Text :
https://doi.org/10.1242/jeb.005272